May 4 marked the 29th anniversary of one of the most controversial episodes in the history of the old South African Defence Force - the Battle of Cassinga in Angola, long represented as a grotesque war crime committed by the SADF against a defenceless refugee camp.

It is a view expressed as recently as 2006 by Annette Hubschle in the Institute for Security Studies journal African Security Review.

Hubschle called the raid "one of the most notorious raids on the Namibian refugee camp of Kassinga in southern Angola on May 4, 1978, South African forces killed over 600 people, most of them women and children".

That is a very serious charge, countered this week by General Constand Viljoen, then chief of the SA Army, planner of the airborne raid on Cassinga and someone who, true to his reputation as a soldier's soldier, was on the ground himself during the battle.

Viljoen, who retired from the SADF in 1985, later played the leading role in getting his fellow generals to accept black majority rule and Nelson Mandela as president rather than embarking on a bloody rearguard action.

He admitted there were a few civilians at Cassinga, but claimed the women were either girlfriends of guerrillas or guerrillas themselves, and flatly denied the "Cassinga massacre" thesis.

The broader context of the SADF's presence in Angola is usually represented as South Africa having illegitimately invaded in October 1975, in a move to extend the range of its racist policies.

But Viljoen this week correctly recalled that South Africa had been invited in to assist two of the three factions in the civil war: Holden Roberto's National Liberation Front of Angola (FNLA), which had absorbed Daniel Chipenda's splinter faction of the Popular Movement for the Liberation of Angola (MPLA), and Jonas Savimbi's National Union for the Total Independence of Angola (Unita).

Angola had been plunged into civil war by the seizure of Luanda and other key towns by Agostinho Neto's majority faction of the MPLA.

The Cuban/Soviet-backed MPLA wanted to prevent the other groupings from sharing power in a transitional government, in defiance of a multi-party agreement struck in 1975.

Although by January 1976 SADF armour was "within sightseeing distance of Luanda", as Viljoen put it, they did not take the capital as their intention was merely to force the MPLA to abide by the power-sharing pact. T

he SADF later withdrew, but conducted raids time and again against Swapo bases in southern Angola that threatened South-West Africa/Namibia.

So what did happen at the tiny ore-mining town of Cassinga, 260km inside Angola?

For the SADF, the raid was one part of a three-pronged attack called Operation Reindeer. It began at 8.02am on May 4, 1978 with an SA Air Force bombing run that softened the position, already clearly marked on aerial reconnaissance photographs with kilometres of trenches and anti-aircraft emplacements.

Claudia Ushona, then a 16-year-old refugee at Cassinga, but now a Namibian diplomat, remembers seeing the bombs falling and initially thinking Sam Nujoma was dropping sweets for the children. Instead, the bombs decimated the Swapo HQ and the parade ground, where many had gathered for Swapo's morning parade.

The Cassinga complex was, Viljoen avers, "a huge logistics support base" from which it was suspected Swapo was gathering its forces for a dramatic push into South-West Africa in order to upset the Turnhalle talks, so the SADF opted for a pre-emptive strike.

The base housed roughly 2 500 guerrillas belonging to Swapo's People's Liberation Army of Namibia (Plan) under commander Dimo Amaambo. In the town itself, however, there were about 1 400 Namibian refugees.

After the bombing run had done its damage, reservist parabats, organised into four under-strength parachute companies led by Colonel Jan Breytenbach of 32 Battalion renown, were dropped into combat.

The fierce and bloody battle that ensued was anything but a walk in the park, lasting a good four hours longer than expected, with the SA forces encountering anti-tank rifle fire and determined resistance from Plan guerrillas in the trenches and from batteries of heavy 14,5mm anti-aircraft guns fired horizontally.

Viljoen recalled: "It is true there were some women and children, but completely untrue to say they made up most of those killed. Swapo had some women in uniform and there were also girlfriends of fighters present.

"When I was standing at the main objective in Cassinga, there were many buildings around me that were apparently magazines, because they were all exploding. "

One veteran parabat, describing Cassinga as "a scene from Dante's Inferno", recalled the bitter battle: "among the dead was a female terr dressed in East German fleck camouflage. She had been shot in the neck while firing at the 'Bats' with an SKS ".

Later, referring to the struggle to knock out the anti-aircraft batteries, he said: "The Bats were in terrible trouble, any movement drew heavy fire. The terrs manning the guns were no 'refugees', the enemy knew their job and there were wounded South Africans out in the open."

Most of the Plan guerrillas fought and "died hard", earning "the grudging respect of their South African opponents".

But the veteran admitted that the battle for the trenches was "bloody butchers' work". He claimed Plan was using civilian women and children in the trenches as human shields, so the parabats had the "grim task" of clearing them out.

Viljoen said the Swapo government of Namibia had been very quiet about Cassinga in recent years because they knew that, in truth, no massacre had occurred.

Yet Cassinga Day is still marked as a public holiday in Namibia, and this year about 20 survivors held a candlelit vigil and told a packed amphitheatre at Katatura of their experiences.

"Cassinga survivor Agnes Kafuta urged the government to bring back the remains of the victims so that they could be buried on home soil," wrote Tanja Bause of The Namibian, who added that Swapo had "already collected soil from the mass grave at Cassinga and buried it at Heroes' Acre in Windhoek".

The screams of Cassinga faded away almost two decades ago, but the battle still lives on in the hearts of the children of those who fought on that day. On Internet blogs they continue to debate the battle.

The daughter of a Plan guerrilla, who was a child at the time, recalled the terror of that day, and lashed out at the son of a parabat, saying "Your father is a terrorist!"

"If that is so," came the reply, "it's something I'm going to have to live with."